The ubuntu:22.04 docker image's bash ignores signal 15 when run as init, so force quit right away.

docker/stop-docker

@@ -1,6 +1,8 @@
 #!/bin/bash
 
-docker stop oram_C &
-docker stop oram_D &
-docker stop oram_E &
+# The ubuntu:22.04 docker image's bash ignores signal 15 when run as init, so
+# force quit right away.
+docker stop -t 0 oram_C &
+docker stop -t 0 oram_D &
+docker stop -t 0 oram_E &
 wait