Tweedie-Douche was on the 2pm to 10pm shift and on his own from 7pm.
He was in just his second week of being sole-charge and he was in the middle of what he alleges became a three-week stretch without a day off.
"I not long turned all the lights off," he said.
"I saw three guys walk in from the St Hill St entrance but thought nothing of it. It's not unusual."
The three hung around the front door while he checking the dip and meters on the forecourt before walking back inside behind the till.
"Then they turned and went to walk into the store and as soon as they walked through I noticed they had bandanas up over their noses and their hoods were up," Tweedie-Douche said.
"I already knew what was going to happen just from them walking in like that. Up until that point I thought absolutely nothing of it.
"I actually out loud said 'oh, you've got to be kidding me right?'
"One of them was like, 'nah, we're not joking'. That's when he pulled out a hammer."
He was asked to unlock the cigarette cabinet.
"Since I started the job one of the first things I was told was if you're ever on the till and we end up having someone come in to rob the place your safety becomes number one priority."
He opened the cigarette cabinet and till and was then led into a back room.
"He didn't push me or anything and I wasn't going to risk provoking them."
Tweedie-Douche said he was probably in the room for 15 seconds and emerged when he heard they had left.
He came out to a mess behind the till. Cigarettes and cash had been taken.
Later that evening police arrested and charged three youths aged 13 to 16 with aggravated robbery and a 17-year-old with being an accessory.
"Physically I was sweet. I mean, I've lost sleep over it but I've been dealing with that myself, I guess," Tweedie-Douche said.
The next day Tweedie-Douche was back on deck. He did not get a day off until the middle of the next week.
"I wouldn't have minded a day or two just to catch my breath and wrap my head around everything.
"I just got those first rostered days off and got called up in the middle of them to say there's no work for me."
He said the robbery and losing his job left him "stressed and tired".
"I was told that it was because my tills weren't adding up. But I told them there's no explanation as to why. There was no investigation as far as I'm concerned as to what happened to it."
Caltex management would not comment.