Difference between Go in at the deep end and Go off at the deep end

go in at the deep end—do smth. difficult without preparation or with no experience of it:

• You will not be expected to go in at the deep end and you will get support from staff members.

go off at the deep end—(also: go off the deep end) lose one’s temper; act recklessly or hysterically:

• I saw what he had done, and I just went off at the deep end.