Select your targets with equal care. That convoy of three adults with four children in wheelchairs are ideal. They won't mind at all if you jump in front of them as they puff their way up the hill - see point one above, re: needing to pause for breath.
Pick your moment. If you notice the group has waved you off for a minute, don't be put off. Step in front of them again. Speak loudly in order to be heard over the strangely insistent alarm sounding from the machine attached to one of the children. Don't be put off by the frantic rummaging through medical looking kit, the odd colour of the child with the machines attached, and the slightly stressed look of the adults as they appear to be telling the child to breathe. Who knows, this could be that child's last opportunity to hear the Good News?
I admire your determination to share the word against all the odds. But here's a thought:
You saw us. You watched us, you stepped in front of us, making our way harder. Perhaps another time you could come alongside, even offer to help push. Meet us where we are, see to the most pressing need.
A bit of physical exertion on your part would have given you the opportunity to talk to us far more naturally. And instead of having a little prepared card to read from, you might have been blessed by an actual real conversation. Of course, that conversation would have shown you that half of us were already pretty familiar with the Good News of Christ (and the other half equally secure in their own pre messianic faith), but it might have been an interesting conversation nevertheless. And we'd definitely have been thankful for your help.
Please, guys, open your eyes. At the risk of sounding a little clichéd, what would Jesus do? I'm pretty sure He wouldn't have been making a difficult situation worse.
You ran away pretty quickly when we suggested now was possibly not the best time. Thank you for not pressing the point, but again, if you'd looked at the whole situation and not just your memory card, perhaps you might have thought to offer help? We didn't need an ambulance, but offering to call one - or to clear a path through the crowds to a quieter spot - might once again have given you an opportunity to share your news, whilst also giving you the opportunity to serve. Actions speak volumes.
I'm sure you won't read this, so instead I'll shout out a big thank you to those Street Pastors we know both locally and further afield, who take the opportunity to be Jesus to the people they meet, in order that those people might see Jesus in them. It's probably a bit messier than throwing yourself under a passing wheelchair convoy clutching a little script. But it's almost certainly more effective.