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Chapter 17 — Contained laboratory II

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Chapter 17 — Contained laboratory II

Lesson map

Lesson 17 published. Map, example, EX065.

flowchart TD
  N0["Learning outcomes"]
  N1["17.1 Build"]
  N2["17.2 Stop drill"]
  N3["17.3 Evidence index"]
  N4["17.4 Peer challenge"]
  N5["17.5 Time box"]
  N6["17.6 Pass bar"]
  N7["17.7 Stress without harm"]
  N0 --> N1 --> N2 --> N3 --> N4 --> N5 --> N6 --> N7
  N7 --> EX["Worked example"]
  EX --> Q["Exercise EX065"]

Logical drawing

flowchart LR
  N0["Learning outcomes"]
  N1["17.1 Build"]
  N2["17.2 Stop drill"]
  N3["17.3 Evidence index"]
  N4["17.4 Peer challenge"]
  N5["17.5 Time box"]
  N6["17.6 Pass bar"]
  N7["17.7 Stress without harm"]
  N0 --> N1 --> N2 --> N3 --> N4 --> N5 --> N6 --> N7 --> Q["EX065"]

[Learning outcomes]
    |
    v
[17.1 Build]
    |
    v
[17.2 Stop drill]
    |
    v
[17.3 Evidence index]
    |
    v
[17.4 Peer challenge]
    |
    v
[17.5 Time box]
    |
    v
[17.6 Pass bar]
    |
    v
[17.7 Stress without harm]
    |
    v
[Worked example] --> [Exercise EX065]

Learning outcomes

You will (1) combine method cards with labs; (2) produce a mini retest report; (3) handle a mid-lab stop drill; (4) submit evidence indexed by hash.

17.1 Build

Create one method card; run lab_retest; write a one-page retest report.

Lab II builds a mini ENG-512 around that card: inventory, lab_ports, hashed evidence, a stop drill and retest statuses. Learners reuse the Lab I inventory with a fresh planted fault, so a remembered answer from the first lab does not pass. To pass, the learner must find the planted NOT APPROVED listener and deliver a rehearsed stop message, alongside the hashes and the retest table that make up the deliverable set.

17.2 Stop drill

At a random time the supervisor calls stop; learner must post a compliant stop message within two minutes.

The drill replays the 401 loop: halt, post the ENG-512 stop message with the time, and wait for guidance. A learner who continues after the loop to finish one more objective fails Lab II, however close that objective seemed. Halting and posting come first, because the habit being graded is stopping on cue, and a live engagement will not offer a convenient moment to wrap up the current task.

17.3 Evidence index

Table of file, hash, finding id.

The Lab II evidence index lists every PNG and TXT file with its hash prefix. Any MISMATCH row must show two-person approval before the expected hash is updated. Graders open the index first and grade its completeness before reading any narrative, and narrative chapters earn zero points if the index is incomplete. The order reflects real casework, where a well-written story cannot rescue evidence whose integrity cannot be shown. Hash prefixes in the index must also match the files in the vault copy that the grader opens.

17.4 Peer challenge

Peer tries to get you to attach a mismatched file; you refuse.

The peer challenge also hunts for a missing fare exclusion or an empty emergency contact. Calm repair of a gap scores well, while defensive arguing loses points even if the artefact is later fixed. The score sheet keeps tone and artefact quality in separate columns, so a learner who repairs the notebook gracefully is credited for both, and a correct artefact defended badly still shows the lost tone points.

17.5 Time box

Two hours.

The Lab II time box is fixed on the course calendar. When the calendar bell rings, typing stops, and any overrun is recorded as a written note titled overrun that lists what remained unfinished. Silent extra minutes are not allowed, because the lab is practising the discipline of a real engagement window, where work outside the agreed time is unauthorised regardless of how close the learner was to finishing. The overrun note is graded honestly, and an unfinished item listed there costs less than hidden extra work.

17.6 Pass bar

Stop drill + refusal + coherent report.

In detail, the pass bar has four parts: the planted fault reported, the stop drill clean, every hash showing MATCH or an explained MISMATCH, and the peer check passed. Missing any one of the four fails Lab II, even with perfect demeanour. Charm and confident presentation do not substitute for those artefacts, because an examiner reviewing the portfolio later sees only the files, not how the learner sounded. Graders record which of the four failed, so the learner knows exactly what to repeat.

17.7 Stress without harm

The stop drill is stressful on purpose; harming systems is not. Supervisors never plant production-impacting faults.

Stress without harm means synthetic load only. No Lab II scenario touches real fare equipment or rider production systems, and the prop list for the lab explicitly forbids fare hardware and production data. The pressure comes from the clock and the random stop call, not from any risk to real systems, so a learner's mistake under stress costs marks rather than service for riders.

17.8 After-action

Each Lab II ends with three minutes of after-action: what almost went wrong, what to change in the runbook.

The after-action produces three improvements for the next ENG-512. Each improvement is ticketed and linked from the Lab II report before sign-off, and the supervisor will not ink the sign-off until all three tickets exist. Without them, Lab II stays incomplete on the roster. Requiring tickets rather than spoken ideas means the lessons from a near miss actually reach the runbook instead of fading after the session.

17.9 Field discipline

Laboratory II's peer challenge is play-acting pressure: "just attach it, the hash is close enough". The correct answer is always refuse. Sam has heard similar pressure in real engagements about unverified scanner output. Practising the refusal with a peer makes the real refusal easier.

Field discipline for Lab II is drill, evidence, peer challenge, pass bar. The lab exists to make ENG-512 boringly safe. Two parts of the pass bar in 17.6 are never negotiable: the planted NOT APPROVED listener must be found and the stop message must be rehearsed cleanly.

17.10 Closing note

Sam's stop message in the drill uses the same template as production engagements, so wording muscle memory transfers. Fancy prose is discouraged; facts win.

Lab II is the last gate before Sam's project, and a failed stop drill blocks portfolio credit until it is rehearsed clean. The block is enforced in practice: project repositories stay locked until the learner's stop drill shows a clean peer pass, so the gate cannot be skipped by starting the project early. A learner who fails the drill simply rehearses again until it is clean.

17.11 Extra

If the stop drill message is late, the lab fails even if the report is perfect. Speed of stopping is the skill being measured.

As an extra, Sam keeps the Lab II stop message text as a template in the runbook, and real ENG-512 stops copy its structure rather than freestyle prose. Because the template is now the live one, any pull request that changes it needs sign-off from the Lab II cohort. That keeps the rehearsed wording and the live wording identical, so the habit learned in the drill is the habit used on Saturday.

Worked example (synthetic NMT)

Sam posts a stop message in 50 seconds during the drill, refuses a bad screenshot, and files a retest report with F2 still open.

Synthetic case — Northline Municipal Transit (NMT). The transit agency, Sam Park and all figures are invented for teaching.

Errors and limits

Live transit systems and fare equipment are never tested without a separate, specialised authorization. This book uses synthetic data only and grants no authority to test real systems.

Exercises

Synthesis

Laboratory II adds stop discipline and honest retest reporting under pressure.

Continue studying — chapter 17 of 18

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