He played in a role behind Evans and Cameron Archer in that second-half run out in what was very much a damage limitation exercise.
The 45 minutes he got was his longest appearance yet during an injury-hit loan spell.
It was Murphy’s ninth first-team game in a Preston shirt, all of them coming from the bench.
The seven appearances he made up until October when he first got injured, totalled just 70 minutes of football.
A torn ankle ankle ligament sustained in training kept him out until the turn of the year, then he sustained a calf injury when he was attempting to regain full fitness.
Murphy’s first slice of action under Ryan Lowe’s management was a fortnight ago, with him playing 15 minutes at right wing-back in the 2-1 victory over Bournemouth at Deepdale.
He had to sit out last week’s 0-0 draw at Cardiff as the Bluebirds are his parent club.
Lowe brought him back into the matchday squad at Luton and the PNE boss chose to introduce him at half-time.
Murphy had two sights of goal, meeting a cut back from Brad Potts and firing a first-time shot over the angle of bar and post – a shot he should have put on target.
Soon after, the 28-year-old forced Hatters goalkeeper James Shea into a save at his near post. That was one of only two efforts North End had on target, Cameron Archer denied by Shea in the first half after breaking into the box.
Statistics recorded by Whoscored.com showed Murphy and Evans both had 26 touches of the ball in the second half – two more than Emil Riis had in the opening 45 minutes.
Riis made way for Evans with Murphy taking over from Ali McCann, that change needing a reshuffle.
Daniel Johnson moved to left wing-back to take McCann’s place, Murphy taking up a No.10 role with Alan Browne and Ben Whiteman behind.
Other stats from the game showed that Evans and Sepp van den Berg won the most number of aerials in the North End team – five apiece.
Andrew Hughes had the most touches of any player on the pitch, with 84 touches. Van den Berg was next with 75 touches.
Bambo Diaby was the second PNE player to score an own goal, Van den Berg having done so at Huddersfield in the third league game of the season in August.
It was one the central defender couldn’t really avoid, Daniel Iversen’s save from Amari’i Bell’s shot rebounding against his head and going in.
Only once before Wednesday night had North End shipped four goals in a game this season, the other time on the opening day when Hull City won 4-1 at Deepdale.
It was their biggest defeat since Brentford beat them 5-0 in April, while they lost 4-0 at Cardiff 13 months ago.
North End are now in a two-and-a-half-week break in action, with them not returning to action until April 2 against Derby County at Pride Park.