▼ L&N 23.75 has “had awakened” here. It is more in keeping with contemporary English style, however, to keep the two verbal ideas parallel in terms of tense (“when the jailer woke up and saw”) although logically the second action is subsequent to the first.

▼ The additional semantic component “standing” is supplied (“standing open”) to convey a stative nuance in English.

▼ Was about to kill himself. The jailer’s penalty for failing to guard the prisoners would have been death, so he contemplated saving the leaders the trouble (see Acts 12:19; 27:42).

▼ Or “thought.”