script/test-e2e and script/test-e2e-firefox tagged their image with one fixed name. When two clones ran a suite at once, the second build moved that tag, the image store deleted the first run's now-untagged image, and that suite exited 125 without running a test. Each run now tags its image with the suite's name and twelve random hex digits, runs it by that tag, and removes it in the scripts' existing exit and interrupt cleanup, so no run leaves an image behind. The image-ID file that guarded against a moving tag is no longer needed. README.md's End-to-End Tests section says so. Model: opus-5-5