After each crash, the critical paths are recomputed before the next step is trusted.
Both paths
A-B-D and A-C-D are now tied at length 7.
TABD=TACD=7
Two critical paths
There are 2 critical paths after the first crash.
critical paths=2
Shared activity
To reduce both path lengths with one crash, the displayed plan uses an activity shared by both paths.
shared activity reduces both paths
Recompute note
The critical set changed, so the next crash is chosen from the recomputed state.
critical paths are recomputed