Luke seems far less concerned with the failure of the disciples in prayer than Matthew and Mark were. The disciples slept on account of grief. The description of Jesus sweating great drops of bloos may be a textual variant and may not be original.
He points out the Jesus went out to pray on the Mount of Olives because it was his "Ethos". Oh God, make it my ethos to pray. Make it the ethos of our church to pray.
During the arrest, Jesus asked why they didn't take him during the day at the temple, then he said, "This is your hour and the authority of darkness." Creepy!
The denials are more matter of fact here than in Mark, until the end when Luke records Jesus looking at Peter after the rooster crows!
At the trial Jesus said, "If I answer you, you won't believe me and you'll condemn me." Then he answered them and they condemned him. Hmmm.