I haven't gone through these estimates closely, but
1) how is transfer from Union GO Station to Union subway station in 2.5 minutes? Last time I tried to transfer, I was near the Bay West teamway, and I was about 8 minutes from the GO platform to the subway platform. It's very busy at rush hour, you can't even walk fast. And then I still had to wait for a subway train. And that was from the the top of the stairs, not including the time to get off the GO train, doors to open, etc. And I wasn't even on the southerly outdoor platforms the Lakeshore East line often arrives on!
2) 5 minutes to transfer to RER? Average wait time would be 7.5 minutes. And surely another couple of minutes to transfer (though I'm not too familiar with walking distance at Guildwood.
3) TTC's scheduled time from Bloor to Dundas is 3 minutes, not 4 minutes. Dundas is 3 stations south of Bloor and 3 stations north of Union. Distances are similar. Should use same time.
UTSC to Dundas Station via Lakeshore East RER can be achieved pretty much right now with a good meet of the 198 bus and the Lakeshore GO service. Which means that if it is only 45.5 minutes, I should be able to get something close to that right now with Google Maps -
https://maps.google.ca/maps?saddr=4...exp=0&noal=0&sort=def&mra=ls&t=m&z=12&start=0
I've tried consistently at several times of day, and the best I can get is 55 minutes - unless you catch the VIA train from Guildwood to Union! Then you can do it in about 44 minutes. But I don't think we are envisioning the Lakeshore RER running non-stop at 150 km/hr.